#include <stdint.h>
#include <string.h>
-/*
- * Hash Functions
- * --------------
- *
- * For hash function 'xxx', the following elements are defined:
- *
- * br_xxx_vtable
- * An externally defined instance of br_hash_class.
- *
- * br_xxx_SIZE
- * A macro that evaluates to the output size (in bytes) of the
- * hash function.
- *
- * br_xxx_ID
- * A macro that evaluates to a symbolic identifier for the hash
- * function. Such identifiers are used with HMAC and signature
- * algorithm implementations.
- * NOTE: the numerical value of these identifiers MUST match the
- * constants for hash function identification in TLS 1.2 (see RFC
- * 5246, section 7.4.1.4.1). These are values 1 to 6, for MD5,
- * SHA-1, SHA-224, SHA-256, SHA-384 and SHA-512, respectively.
- *
- * br_xxx_context
- * Context for an ongoing computation. It is allocated by the
- * caller, and a pointer to it is passed to all functions. A
- * context contains no interior pointer, so it can be moved around
- * and cloned (with a simple memcpy() or equivalent) in order to
- * capture the function state at some point. Computations that use
- * distinct context structures are independent of each other. The
- * first field of br_xxx_context is always a pointer to the
- * br_xxx_vtable structure; br_xxx_init() sets that pointer.
- *
- * br_xxx_init(br_xxx_context *ctx)
- * Initialize the provided context. Previous contents of the structure
- * are ignored. This calls resets the context to the start of a new
- * hash computation.
- *
- * br_xxx_update(br_xxx_context *ctx, const void *data, size_t len)
- * Add some more bytes to the hash computation represented by the
- * provided context.
- *
- * br_xxx_out(const br_xxx_context *ctx, void *out)
- * Complete the hash computation and write the result in the provided
- * buffer. The output buffer MUST be large enough to accomodate the
- * result. The context is NOT modified by this operation, so this
- * function can be used to get a "partial hash" while still keeping
- * the possibility of adding more bytes to the input.
- *
- * br_xxx_state(const br_xxx_context *ctx, void *out)
- * Get a copy of the "current state" for the computation so far. For
- * MD functions (MD5, SHA-1, SHA-2 family), this is the running state
- * resulting from the processing of the last complete input block.
- * Returned value is the current input length (in bytes).
- *
- * br_xxx_set_state(br_xxx_context *ctx, const void *stb, uint64_t count)
- * Set the internal state to the provided values. The 'stb' and 'count'
- * values shall match that which was obtained from br_xxx_state(). This
- * restores the hash state only if the state values were at an
- * appropriate block boundary. This does NOT set the 'vtable' pointer
- * in the context.
+/** \file bearssl_hash.h
+ *
+ * # Hash Functions
+ *
+ * This file documents the API for hash functions.
+ *
+ *
+ * ## Procedural API
+ *
+ * For each implemented hash function, of name "`xxx`", the following
+ * elements are defined:
+ *
+ * - `br_xxx_vtable`
+ *
+ * An externally defined instance of `br_hash_class`.
+ *
+ * - `br_xxx_SIZE`
+ *
+ * A macro that evaluates to the output size (in bytes) of the
+ * hash function.
+ *
+ * - `br_xxx_ID`
+ *
+ * A macro that evaluates to a symbolic identifier for the hash
+ * function. Such identifiers are used with HMAC and signature
+ * algorithm implementations.
+ *
+ * NOTE: for the "standard" hash functions defined in [the TLS
+ * standard](https://tools.ietf.org/html/rfc5246#section-7.4.1.4.1),
+ * the symbolic identifiers match the constants used in TLS, i.e.
+ * 1 to 6 for MD5, SHA-1, SHA-224, SHA-256, SHA-384 and SHA-512,
+ * respectively.
+ *
+ * - `br_xxx_context`
+ *
+ * Context for an ongoing computation. It is allocated by the
+ * caller, and a pointer to it is passed to all functions. A
+ * context contains no interior pointer, so it can be moved around
+ * and cloned (with a simple `memcpy()` or equivalent) in order to
+ * capture the function state at some point. Computations that use
+ * distinct context structures are independent of each other. The
+ * first field of `br_xxx_context` is always a pointer to the
+ * `br_xxx_vtable` structure; `br_xxx_init()` sets that pointer.
+ *
+ * - `br_xxx_init(br_xxx_context *ctx)`
+ *
+ * Initialise the provided context. Previous contents of the structure
+ * are ignored. This calls resets the context to the start of a new
+ * hash computation; it also sets the first field of the context
+ * structure (called `vtable`) to a pointer to the statically
+ * allocated constant `br_xxx_vtable` structure.
+ *
+ * - `br_xxx_update(br_xxx_context *ctx, const void *data, size_t len)`
+ *
+ * Add some more bytes to the hash computation represented by the
+ * provided context.
+ *
+ * - `br_xxx_out(const br_xxx_context *ctx, void *out)`
+ *
+ * Complete the hash computation and write the result in the provided
+ * buffer. The output buffer MUST be large enough to accomodate the
+ * result. The context is NOT modified by this operation, so this
+ * function can be used to get a "partial hash" while still keeping
+ * the possibility of adding more bytes to the input.
+ *
+ * - `br_xxx_state(const br_xxx_context *ctx, void *out)`
+ *
+ * Get a copy of the "current state" for the computation so far. For
+ * MD functions (MD5, SHA-1, SHA-2 family), this is the running state
+ * resulting from the processing of the last complete input block.
+ * Returned value is the current input length (in bytes).
+ *
+ * - `br_xxx_set_state(br_xxx_context *ctx, const void *stb, uint64_t count)`
+ *
+ * Set the internal state to the provided values. The 'stb' and
+ * 'count' values shall match that which was obtained from
+ * `br_xxx_state()`. This restores the hash state only if the state
+ * values were at an appropriate block boundary. This does NOT set
+ * the `vtable` pointer in the context.
*
* Context structures can be discarded without any explicit deallocation.
* Hash function implementations are purely software and don't reserve
* any resources outside of the context structure itself.
*
- * Implemented hash functions are:
*
- * Function Name Output length State length
+ * ## Object-Oriented API
+ *
+ * For each hash function that follows the procedural API described
+ * above, an object-oriented API is also provided. In that API, function
+ * pointers from the vtable (`br_xxx_vtable`) are used. The vtable
+ * incarnates object-oriented programming. An introduction on the OOP
+ * concept used here can be read on the BearSSL Web site:<br />
+ * [https://www.bearssl.org/oop.html](https://www.bearssl.org/oop.html)
+ *
+ * The vtable offers functions called `init()`, `update()`, `out()`,
+ * `set()` and `set_state()`, which are in fact the functions from
+ * the procedural API. That vtable also contains two informative fields:
+ *
+ * - `context_size`
+ *
+ * The size of the context structure (`br_xxx_context`), in bytes.
+ * This can be used by generic implementations to perform dynamic
+ * context allocation.
+ *
+ * - `desc`
+ *
+ * A "descriptor" field that encodes some information on the hash
+ * function: symbolic identifier, output size, state size,
+ * internal block size, details on the padding.
+ *
+ * Users of this object-oriented API (in particular generic HMAC
+ * implementations) may make the following assumptions:
*
- * MD5 md5 16 16
- * SHA-1 sha1 20 20
- * SHA-224 sha224 28 32
- * SHA-256 sha256 32 32
- * SHA-384 sha384 48 64
- * SHA-512 sha512 64 64
- * MD5+SHA-1 md5sha1 36 36
+ * - Hash output size is no more than 64 bytes.
+ * - Hash internal state size is no more than 64 bytes.
+ * - Internal block size is a power of two, no less than 16 and no more
+ * than 256.
+ *
+ *
+ * ## Implemented Hash Functions
+ *
+ * Implemented hash functions are:
+ *
+ * | Function | Name | Output length | State length |
+ * | :-------- | :------ | :-----------: | :----------: |
+ * | MD5 | md5 | 16 | 16 |
+ * | SHA-1 | sha1 | 20 | 20 |
+ * | SHA-224 | sha224 | 28 | 32 |
+ * | SHA-256 | sha256 | 32 | 32 |
+ * | SHA-384 | sha384 | 48 | 64 |
+ * | SHA-512 | sha512 | 64 | 64 |
+ * | MD5+SHA-1 | md5sha1 | 36 | 36 |
*
* (MD5+SHA-1 is the concatenation of MD5 and SHA-1 computed over the
* same input; in the implementation, the internal data buffer is
* 1.1.)
*
*
- * An object-oriented API is also available: the first field of the
- * context is a pointer to a br_hash_class structure, that has the
- * following contents:
- *
- * context_size total size of the required context structure
- * desc descriptor (see below)
- * init context initialization or reset (function pointer)
- * update process some more bytes (function pointer)
- * out get hash output so far (function pointer)
- * state get copy of internal state (function pointer)
- * set_state reset the internal state (function pointer)
- *
- * The descriptor is a combination of the following elements:
- * bits 0 to 7 hash algorithm identifier
- * bits 8 to 14 hash output size (in bytes)
- * bits 15 to 22 hash internal state size (in bytes)
- * bits 23 to 26 log (base 2) of hash internal block size (in bytes)
- * bit 28 1 if using MD padding, 0 otherwise
- * bit 29 1 if MD padding uses a 128-bit bit length, 0 otherwise
- * bit 30 1 if MD padding is big-endian, 0 otherwise
- *
- * For function 'xxx', the br_xxx_init() function sets the first field
- * to a pointer to the relevant br_hash_class instance (i.e.
- * br_xxx_vtable).
- *
- * Users of this object-oriented API may make the following assumptions:
- * Hash output size is no more than 64 bytes.
- * Hash internal state size is no more than 64 bytes.
- * Internal block size is a power of two, no less than 2^4 and no more
- * than 2^8.
- * For functions that do not have an internal block size that is a
- * power of 2, the relevant element is 0.
+ * ## Multi-Hasher
+ *
+ * An aggregate hasher is provided, that can compute several standard
+ * hash functions in parallel. It uses `br_multihash_context` and a
+ * procedural API. It is configured with the implementations (the vtables)
+ * that it should use; it will then compute all these hash functions in
+ * parallel, on the same input. It is meant to be used in cases when the
+ * hash of an object will be used, but the exact hash function is not
+ * known yet (typically, streamed processing on X.509 certificates).
+ *
+ * Only the standard hash functions (MD5, SHA-1, SHA-224, SHA-256, SHA-384
+ * and SHA-512) are supported by the multi-hasher.
+ *
+ *
+ * ## GHASH
+ *
+ * GHASH is not a generic hash function; it is a _universal_ hash function,
+ * which, as the name does not say, means that it CANNOT be used in most
+ * places where a hash function is needed. GHASH is used within the GCM
+ * encryption mode, to provide the checked integrity functionality.
+ *
+ * A GHASH implementation is basically a function that uses the type defined
+ * in this file under the name `br_ghash`:
+ *
+ * typedef void (*br_ghash)(void *y, const void *h, const void *data, size_t len);
+ *
+ * The `y` pointer refers to a 16-byte value which is used as input, and
+ * receives the output of the GHASH invocation. `h` is a 16-byte secret
+ * value (that serves as key). `data` and `len` define the input data.
+ *
+ * Three GHASH implementations are provided, all constant-time, based on
+ * the use of integer multiplications with appropriate masking to cancel
+ * carry propagation.
*/
+/**
+ * \brief Class type for hash function implementations.
+ *
+ * A `br_hash_class` instance references the methods implementing a hash
+ * function. Constant instances of this structure are defined for each
+ * implemented hash function. Such instances are also called "vtables".
+ *
+ * Vtables are used to support object-oriented programming, as
+ * described on [the BearSSL Web site](https://www.bearssl.org/oop.html).
+ */
typedef struct br_hash_class_ br_hash_class;
struct br_hash_class_ {
+ /**
+ * \brief Size (in bytes) of the context structure appropriate for
+ * computing this hash function.
+ */
size_t context_size;
+
+ /**
+ * \brief Descriptor word that contains information about the hash
+ * function.
+ *
+ * For each word `xxx` described below, use `BR_HASHDESC_xxx_OFF`
+ * and `BR_HASHDESC_xxx_MASK` to access the specific value, as
+ * follows:
+ *
+ * (hf->desc >> BR_HASHDESC_xxx_OFF) & BR_HASHDESC_xxx_MASK
+ *
+ * The defined elements are:
+ *
+ * - `ID`: the symbolic identifier for the function, as defined
+ * in [TLS](https://tools.ietf.org/html/rfc5246#section-7.4.1.4.1)
+ * (MD5 = 1, SHA-1 = 2,...).
+ *
+ * - `OUT`: hash output size, in bytes.
+ *
+ * - `STATE`: internal running state size, in bytes.
+ *
+ * - `LBLEN`: base-2 logarithm for the internal block size, as
+ * defined for HMAC processing (this is 6 for MD5, SHA-1, SHA-224
+ * and SHA-256, since these functions use 64-byte blocks; for
+ * SHA-384 and SHA-512, this is 7, corresponding to their
+ * 128-byte blocks).
+ *
+ * The descriptor may contain a few other flags.
+ */
uint32_t desc;
+
+ /**
+ * \brief Initialisation method.
+ *
+ * This method takes as parameter a pointer to a context area,
+ * that it initialises. The first field of the context is set
+ * to this vtable; other elements are initialised for a new hash
+ * computation.
+ *
+ * \param ctx pointer to (the first field of) the context.
+ */
void (*init)(const br_hash_class **ctx);
+
+ /**
+ * \brief Data injection method.
+ *
+ * The `len` bytes starting at address `data` are injected into
+ * the running hash computation incarnated by the specified
+ * context. The context is updated accordingly. It is allowed
+ * to have `len == 0`, in which case `data` is ignored (and could
+ * be `NULL`), and nothing happens.
+ * on the input data.
+ *
+ * \param ctx pointer to (the first field of) the context.
+ * \param data pointer to the first data byte to inject.
+ * \param len number of bytes to inject.
+ */
void (*update)(const br_hash_class **ctx, const void *data, size_t len);
+
+ /**
+ * \brief Produce hash output.
+ *
+ * The hash output corresponding to all data bytes injected in the
+ * context since the last `init()` call is computed, and written
+ * in the buffer pointed to by `dst`. The hash output size depends
+ * on the implemented hash function (e.g. 16 bytes for MD5).
+ * The context is _not_ modified by this call, so further bytes
+ * may be afterwards injected to continue the current computation.
+ *
+ * \param ctx pointer to (the first field of) the context.
+ * \param dst destination buffer for the hash output.
+ */
void (*out)(const br_hash_class *const *ctx, void *dst);
+
+ /**
+ * \brief Get running state.
+ *
+ * This method saves the current running state into the `dst`
+ * buffer. What constitutes the "running state" depends on the
+ * hash function; for Merkle-Damgård hash functions (like
+ * MD5 or SHA-1), this is the output obtained after processing
+ * each block. The number of bytes injected so far is returned.
+ * The context is not modified by this call.
+ *
+ * \param ctx pointer to (the first field of) the context.
+ * \param dst destination buffer for the state.
+ * \return the injected total byte length.
+ */
uint64_t (*state)(const br_hash_class *const *ctx, void *dst);
+
+ /**
+ * \brief Set running state.
+ *
+ * This methods replaces the running state for the function.
+ *
+ * \param ctx pointer to (the first field of) the context.
+ * \param stb source buffer for the state.
+ * \param count injected total byte length.
+ */
void (*set_state)(const br_hash_class **ctx,
const void *stb, uint64_t count);
};
+#ifndef BR_DOXYGEN_IGNORE
#define BR_HASHDESC_ID(id) ((uint32_t)(id) << BR_HASHDESC_ID_OFF)
#define BR_HASHDESC_ID_OFF 0
#define BR_HASHDESC_ID_MASK 0xFF
#define BR_HASHDESC_MD_PADDING ((uint32_t)1 << 28)
#define BR_HASHDESC_MD_PADDING_128 ((uint32_t)1 << 29)
#define BR_HASHDESC_MD_PADDING_BE ((uint32_t)1 << 30)
+#endif
/*
* Specific hash functions.
* current state; and there is no need for any explicit "release" function.
*/
+/**
+ * \brief Symbolic identifier for MD5.
+ */
#define br_md5_ID 1
+
+/**
+ * \brief MD5 output size (in bytes).
+ */
#define br_md5_SIZE 16
+
+/**
+ * \brief Constant vtable for MD5.
+ */
extern const br_hash_class br_md5_vtable;
+
+/**
+ * \brief MD5 context.
+ *
+ * First field is a pointer to the vtable; it is set by the initialisation
+ * function. Other fields are not supposed to be accessed by user code.
+ */
typedef struct {
+ /**
+ * \brief Pointer to vtable for this context.
+ */
const br_hash_class *vtable;
+#ifndef BR_DOXYGEN_IGNORE
unsigned char buf[64];
uint64_t count;
uint32_t val[4];
+#endif
} br_md5_context;
+
+/**
+ * \brief MD5 context initialisation.
+ *
+ * This function initialises or resets a context for a new MD5
+ * computation. It also sets the vtable pointer.
+ *
+ * \param ctx pointer to the context structure.
+ */
void br_md5_init(br_md5_context *ctx);
+
+/**
+ * \brief Inject some data bytes in a running MD5 computation.
+ *
+ * The provided context is updated with some data bytes. If the number
+ * of bytes (`len`) is zero, then the data pointer (`data`) is ignored
+ * and may be `NULL`, and this function does nothing.
+ *
+ * \param ctx pointer to the context structure.
+ * \param data pointer to the injected data.
+ * \param len injected data length (in bytes).
+ */
void br_md5_update(br_md5_context *ctx, const void *data, size_t len);
+
+/**
+ * \brief Compute MD5 output.
+ *
+ * The MD5 output for the concatenation of all bytes injected in the
+ * provided context since the last initialisation or reset call, is
+ * computed and written in the buffer pointed to by `out`. The context
+ * itself is not modified, so extra bytes may be injected afterwards
+ * to continue that computation.
+ *
+ * \param ctx pointer to the context structure.
+ * \param out destination buffer for the hash output.
+ */
void br_md5_out(const br_md5_context *ctx, void *out);
+
+/**
+ * \brief Save MD5 running state.
+ *
+ * The running state for MD5 (output of the last internal block
+ * processing) is written in the buffer pointed to by `out`. The
+ * number of bytes injected since the last initialisation or reset
+ * call is returned. The context is not modified.
+ *
+ * \param ctx pointer to the context structure.
+ * \param out destination buffer for the running state.
+ * \return the injected total byte length.
+ */
uint64_t br_md5_state(const br_md5_context *ctx, void *out);
+
+/**
+ * \brief Restore MD5 running state.
+ *
+ * The running state for MD5 is set to the provided values.
+ *
+ * \param ctx pointer to the context structure.
+ * \param stb source buffer for the running state.
+ * \param count the injected total byte length.
+ */
void br_md5_set_state(br_md5_context *ctx, const void *stb, uint64_t count);
+/**
+ * \brief Symbolic identifier for SHA-1.
+ */
#define br_sha1_ID 2
+
+/**
+ * \brief SHA-1 output size (in bytes).
+ */
#define br_sha1_SIZE 20
+
+/**
+ * \brief Constant vtable for SHA-1.
+ */
extern const br_hash_class br_sha1_vtable;
+
+/**
+ * \brief SHA-1 context.
+ *
+ * First field is a pointer to the vtable; it is set by the initialisation
+ * function. Other fields are not supposed to be accessed by user code.
+ */
typedef struct {
+ /**
+ * \brief Pointer to vtable for this context.
+ */
const br_hash_class *vtable;
+#ifndef BR_DOXYGEN_IGNORE
unsigned char buf[64];
uint64_t count;
uint32_t val[5];
+#endif
} br_sha1_context;
+
+/**
+ * \brief SHA-1 context initialisation.
+ *
+ * This function initialises or resets a context for a new SHA-1
+ * computation. It also sets the vtable pointer.
+ *
+ * \param ctx pointer to the context structure.
+ */
void br_sha1_init(br_sha1_context *ctx);
+
+/**
+ * \brief Inject some data bytes in a running SHA-1 computation.
+ *
+ * The provided context is updated with some data bytes. If the number
+ * of bytes (`len`) is zero, then the data pointer (`data`) is ignored
+ * and may be `NULL`, and this function does nothing.
+ *
+ * \param ctx pointer to the context structure.
+ * \param data pointer to the injected data.
+ * \param len injected data length (in bytes).
+ */
void br_sha1_update(br_sha1_context *ctx, const void *data, size_t len);
+
+/**
+ * \brief Compute SHA-1 output.
+ *
+ * The SHA-1 output for the concatenation of all bytes injected in the
+ * provided context since the last initialisation or reset call, is
+ * computed and written in the buffer pointed to by `out`. The context
+ * itself is not modified, so extra bytes may be injected afterwards
+ * to continue that computation.
+ *
+ * \param ctx pointer to the context structure.
+ * \param out destination buffer for the hash output.
+ */
void br_sha1_out(const br_sha1_context *ctx, void *out);
+
+/**
+ * \brief Save SHA-1 running state.
+ *
+ * The running state for SHA-1 (output of the last internal block
+ * processing) is written in the buffer pointed to by `out`. The
+ * number of bytes injected since the last initialisation or reset
+ * call is returned. The context is not modified.
+ *
+ * \param ctx pointer to the context structure.
+ * \param out destination buffer for the running state.
+ * \return the injected total byte length.
+ */
uint64_t br_sha1_state(const br_sha1_context *ctx, void *out);
+
+/**
+ * \brief Restore SHA-1 running state.
+ *
+ * The running state for SHA-1 is set to the provided values.
+ *
+ * \param ctx pointer to the context structure.
+ * \param stb source buffer for the running state.
+ * \param count the injected total byte length.
+ */
void br_sha1_set_state(br_sha1_context *ctx, const void *stb, uint64_t count);
+/**
+ * \brief Symbolic identifier for SHA-224.
+ */
#define br_sha224_ID 3
+
+/**
+ * \brief SHA-224 output size (in bytes).
+ */
#define br_sha224_SIZE 28
+
+/**
+ * \brief Constant vtable for SHA-224.
+ */
extern const br_hash_class br_sha224_vtable;
+
+/**
+ * \brief SHA-224 context.
+ *
+ * First field is a pointer to the vtable; it is set by the initialisation
+ * function. Other fields are not supposed to be accessed by user code.
+ */
typedef struct {
+ /**
+ * \brief Pointer to vtable for this context.
+ */
const br_hash_class *vtable;
+#ifndef BR_DOXYGEN_IGNORE
unsigned char buf[64];
uint64_t count;
uint32_t val[8];
+#endif
} br_sha224_context;
+
+/**
+ * \brief SHA-224 context initialisation.
+ *
+ * This function initialises or resets a context for a new SHA-224
+ * computation. It also sets the vtable pointer.
+ *
+ * \param ctx pointer to the context structure.
+ */
void br_sha224_init(br_sha224_context *ctx);
+
+/**
+ * \brief Inject some data bytes in a running SHA-224 computation.
+ *
+ * The provided context is updated with some data bytes. If the number
+ * of bytes (`len`) is zero, then the data pointer (`data`) is ignored
+ * and may be `NULL`, and this function does nothing.
+ *
+ * \param ctx pointer to the context structure.
+ * \param data pointer to the injected data.
+ * \param len injected data length (in bytes).
+ */
void br_sha224_update(br_sha224_context *ctx, const void *data, size_t len);
+
+/**
+ * \brief Compute SHA-224 output.
+ *
+ * The SHA-224 output for the concatenation of all bytes injected in the
+ * provided context since the last initialisation or reset call, is
+ * computed and written in the buffer pointed to by `out`. The context
+ * itself is not modified, so extra bytes may be injected afterwards
+ * to continue that computation.
+ *
+ * \param ctx pointer to the context structure.
+ * \param out destination buffer for the hash output.
+ */
void br_sha224_out(const br_sha224_context *ctx, void *out);
+
+/**
+ * \brief Save SHA-224 running state.
+ *
+ * The running state for SHA-224 (output of the last internal block
+ * processing) is written in the buffer pointed to by `out`. The
+ * number of bytes injected since the last initialisation or reset
+ * call is returned. The context is not modified.
+ *
+ * \param ctx pointer to the context structure.
+ * \param out destination buffer for the running state.
+ * \return the injected total byte length.
+ */
uint64_t br_sha224_state(const br_sha224_context *ctx, void *out);
+
+/**
+ * \brief Restore SHA-224 running state.
+ *
+ * The running state for SHA-224 is set to the provided values.
+ *
+ * \param ctx pointer to the context structure.
+ * \param stb source buffer for the running state.
+ * \param count the injected total byte length.
+ */
void br_sha224_set_state(br_sha224_context *ctx,
const void *stb, uint64_t count);
+/**
+ * \brief Symbolic identifier for SHA-256.
+ */
#define br_sha256_ID 4
+
+/**
+ * \brief SHA-256 output size (in bytes).
+ */
#define br_sha256_SIZE 32
+
+/**
+ * \brief Constant vtable for SHA-256.
+ */
extern const br_hash_class br_sha256_vtable;
+
+#ifdef BR_DOXYGEN_IGNORE
+/**
+ * \brief SHA-256 context.
+ *
+ * First field is a pointer to the vtable; it is set by the initialisation
+ * function. Other fields are not supposed to be accessed by user code.
+ */
+typedef struct {
+ /**
+ * \brief Pointer to vtable for this context.
+ */
+ const br_hash_class *vtable;
+} br_sha256_context;
+#else
typedef br_sha224_context br_sha256_context;
+#endif
+
+/**
+ * \brief SHA-256 context initialisation.
+ *
+ * This function initialises or resets a context for a new SHA-256
+ * computation. It also sets the vtable pointer.
+ *
+ * \param ctx pointer to the context structure.
+ */
void br_sha256_init(br_sha256_context *ctx);
+
+#ifdef BR_DOXYGEN_IGNORE
+/**
+ * \brief Inject some data bytes in a running SHA-256 computation.
+ *
+ * The provided context is updated with some data bytes. If the number
+ * of bytes (`len`) is zero, then the data pointer (`data`) is ignored
+ * and may be `NULL`, and this function does nothing.
+ *
+ * \param ctx pointer to the context structure.
+ * \param data pointer to the injected data.
+ * \param len injected data length (in bytes).
+ */
+void br_sha256_update(br_sha256_context *ctx, const void *data, size_t len);
+#else
#define br_sha256_update br_sha224_update
+#endif
+
+/**
+ * \brief Compute SHA-256 output.
+ *
+ * The SHA-256 output for the concatenation of all bytes injected in the
+ * provided context since the last initialisation or reset call, is
+ * computed and written in the buffer pointed to by `out`. The context
+ * itself is not modified, so extra bytes may be injected afterwards
+ * to continue that computation.
+ *
+ * \param ctx pointer to the context structure.
+ * \param out destination buffer for the hash output.
+ */
void br_sha256_out(const br_sha256_context *ctx, void *out);
+
+#if BR_DOXYGEN_IGNORE
+/**
+ * \brief Save SHA-256 running state.
+ *
+ * The running state for SHA-256 (output of the last internal block
+ * processing) is written in the buffer pointed to by `out`. The
+ * number of bytes injected since the last initialisation or reset
+ * call is returned. The context is not modified.
+ *
+ * \param ctx pointer to the context structure.
+ * \param out destination buffer for the running state.
+ * \return the injected total byte length.
+ */
+uint64_t br_sha256_state(const br_sha256_context *ctx, void *out);
+#else
#define br_sha256_state br_sha224_state
+#endif
+
+#if BR_DOXYGEN_IGNORE
+/**
+ * \brief Restore SHA-256 running state.
+ *
+ * The running state for SHA-256 is set to the provided values.
+ *
+ * \param ctx pointer to the context structure.
+ * \param stb source buffer for the running state.
+ * \param count the injected total byte length.
+ */
+void br_sha256_set_state(br_sha256_context *ctx,
+ const void *stb, uint64_t count);
+#else
#define br_sha256_set_state br_sha224_set_state
+#endif
+/**
+ * \brief Symbolic identifier for SHA-384.
+ */
#define br_sha384_ID 5
+
+/**
+ * \brief SHA-384 output size (in bytes).
+ */
#define br_sha384_SIZE 48
+
+/**
+ * \brief Constant vtable for SHA-384.
+ */
extern const br_hash_class br_sha384_vtable;
+
+/**
+ * \brief SHA-384 context.
+ *
+ * First field is a pointer to the vtable; it is set by the initialisation
+ * function. Other fields are not supposed to be accessed by user code.
+ */
typedef struct {
+ /**
+ * \brief Pointer to vtable for this context.
+ */
const br_hash_class *vtable;
+#ifndef BR_DOXYGEN_IGNORE
unsigned char buf[128];
uint64_t count;
uint64_t val[8];
+#endif
} br_sha384_context;
+
+/**
+ * \brief SHA-384 context initialisation.
+ *
+ * This function initialises or resets a context for a new SHA-384
+ * computation. It also sets the vtable pointer.
+ *
+ * \param ctx pointer to the context structure.
+ */
void br_sha384_init(br_sha384_context *ctx);
+
+/**
+ * \brief Inject some data bytes in a running SHA-384 computation.
+ *
+ * The provided context is updated with some data bytes. If the number
+ * of bytes (`len`) is zero, then the data pointer (`data`) is ignored
+ * and may be `NULL`, and this function does nothing.
+ *
+ * \param ctx pointer to the context structure.
+ * \param data pointer to the injected data.
+ * \param len injected data length (in bytes).
+ */
void br_sha384_update(br_sha384_context *ctx, const void *data, size_t len);
+
+/**
+ * \brief Compute SHA-384 output.
+ *
+ * The SHA-384 output for the concatenation of all bytes injected in the
+ * provided context since the last initialisation or reset call, is
+ * computed and written in the buffer pointed to by `out`. The context
+ * itself is not modified, so extra bytes may be injected afterwards
+ * to continue that computation.
+ *
+ * \param ctx pointer to the context structure.
+ * \param out destination buffer for the hash output.
+ */
void br_sha384_out(const br_sha384_context *ctx, void *out);
+
+/**
+ * \brief Save SHA-384 running state.
+ *
+ * The running state for SHA-384 (output of the last internal block
+ * processing) is written in the buffer pointed to by `out`. The
+ * number of bytes injected since the last initialisation or reset
+ * call is returned. The context is not modified.
+ *
+ * \param ctx pointer to the context structure.
+ * \param out destination buffer for the running state.
+ * \return the injected total byte length.
+ */
uint64_t br_sha384_state(const br_sha384_context *ctx, void *out);
+
+/**
+ * \brief Restore SHA-384 running state.
+ *
+ * The running state for SHA-384 is set to the provided values.
+ *
+ * \param ctx pointer to the context structure.
+ * \param stb source buffer for the running state.
+ * \param count the injected total byte length.
+ */
void br_sha384_set_state(br_sha384_context *ctx,
const void *stb, uint64_t count);
+/**
+ * \brief Symbolic identifier for SHA-512.
+ */
#define br_sha512_ID 6
+
+/**
+ * \brief SHA-512 output size (in bytes).
+ */
#define br_sha512_SIZE 64
+
+/**
+ * \brief Constant vtable for SHA-512.
+ */
extern const br_hash_class br_sha512_vtable;
+
+#ifdef BR_DOXYGEN_IGNORE
+/**
+ * \brief SHA-512 context.
+ *
+ * First field is a pointer to the vtable; it is set by the initialisation
+ * function. Other fields are not supposed to be accessed by user code.
+ */
+typedef struct {
+ /**
+ * \brief Pointer to vtable for this context.
+ */
+ const br_hash_class *vtable;
+} br_sha512_context;
+#else
typedef br_sha384_context br_sha512_context;
+#endif
+
+/**
+ * \brief SHA-512 context initialisation.
+ *
+ * This function initialises or resets a context for a new SHA-512
+ * computation. It also sets the vtable pointer.
+ *
+ * \param ctx pointer to the context structure.
+ */
void br_sha512_init(br_sha512_context *ctx);
-#define br_sha512_update br_sha384_update
+
+#ifdef BR_DOXYGEN_IGNORE
+/**
+ * \brief Inject some data bytes in a running SHA-512 computation.
+ *
+ * The provided context is updated with some data bytes. If the number
+ * of bytes (`len`) is zero, then the data pointer (`data`) is ignored
+ * and may be `NULL`, and this function does nothing.
+ *
+ * \param ctx pointer to the context structure.
+ * \param data pointer to the injected data.
+ * \param len injected data length (in bytes).
+ */
+void br_sha512_update(br_sha512_context *ctx, const void *data, size_t len);
+#else
+#define br_sha512_update br_sha384_update
+#endif
+
+/**
+ * \brief Compute SHA-512 output.
+ *
+ * The SHA-512 output for the concatenation of all bytes injected in the
+ * provided context since the last initialisation or reset call, is
+ * computed and written in the buffer pointed to by `out`. The context
+ * itself is not modified, so extra bytes may be injected afterwards
+ * to continue that computation.
+ *
+ * \param ctx pointer to the context structure.
+ * \param out destination buffer for the hash output.
+ */
void br_sha512_out(const br_sha512_context *ctx, void *out);
-#define br_sha512_state br_sha384_state
+
+#ifdef BR_DOXYGEN_IGNORE
+/**
+ * \brief Save SHA-512 running state.
+ *
+ * The running state for SHA-512 (output of the last internal block
+ * processing) is written in the buffer pointed to by `out`. The
+ * number of bytes injected since the last initialisation or reset
+ * call is returned. The context is not modified.
+ *
+ * \param ctx pointer to the context structure.
+ * \param out destination buffer for the running state.
+ * \return the injected total byte length.
+ */
+uint64_t br_sha512_state(const br_sha512_context *ctx, void *out);
+#else
+#define br_sha512_state br_sha384_state
+#endif
+
+#ifdef BR_DOXYGEN_IGNORE
+/**
+ * \brief Restore SHA-512 running state.
+ *
+ * The running state for SHA-512 is set to the provided values.
+ *
+ * \param ctx pointer to the context structure.
+ * \param stb source buffer for the running state.
+ * \param count the injected total byte length.
+ */
+void br_sha512_set_state(br_sha512_context *ctx,
+ const void *stb, uint64_t count);
+#else
#define br_sha512_set_state br_sha384_set_state
+#endif
/*
* "md5sha1" is a special hash function that computes both MD5 and SHA-1
* on the same input, and produces a 36-byte output (MD5 and SHA-1
* concatenation, in that order). State size is also 36 bytes.
*/
+
+/**
+ * \brief Symbolic identifier for MD5+SHA-1.
+ *
+ * MD5+SHA-1 is the concatenation of MD5 and SHA-1, computed over the
+ * same input. It is not one of the functions identified in TLS, so
+ * we give it a symbolic identifier of value 0.
+ */
#define br_md5sha1_ID 0
+
+/**
+ * \brief MD5+SHA-1 output size (in bytes).
+ */
#define br_md5sha1_SIZE 36
+
+/**
+ * \brief Constant vtable for MD5+SHA-1.
+ */
extern const br_hash_class br_md5sha1_vtable;
+
+/**
+ * \brief MD5+SHA-1 context.
+ *
+ * First field is a pointer to the vtable; it is set by the initialisation
+ * function. Other fields are not supposed to be accessed by user code.
+ */
typedef struct {
+ /**
+ * \brief Pointer to vtable for this context.
+ */
const br_hash_class *vtable;
+#ifndef BR_DOXYGEN_IGNORE
unsigned char buf[64];
uint64_t count;
uint32_t val_md5[4];
uint32_t val_sha1[5];
+#endif
} br_md5sha1_context;
+
+/**
+ * \brief MD5+SHA-1 context initialisation.
+ *
+ * This function initialises or resets a context for a new SHA-512
+ * computation. It also sets the vtable pointer.
+ *
+ * \param ctx pointer to the context structure.
+ */
void br_md5sha1_init(br_md5sha1_context *ctx);
+
+/**
+ * \brief Inject some data bytes in a running MD5+SHA-1 computation.
+ *
+ * The provided context is updated with some data bytes. If the number
+ * of bytes (`len`) is zero, then the data pointer (`data`) is ignored
+ * and may be `NULL`, and this function does nothing.
+ *
+ * \param ctx pointer to the context structure.
+ * \param data pointer to the injected data.
+ * \param len injected data length (in bytes).
+ */
void br_md5sha1_update(br_md5sha1_context *ctx, const void *data, size_t len);
+
+/**
+ * \brief Compute MD5+SHA-1 output.
+ *
+ * The MD5+SHA-1 output for the concatenation of all bytes injected in the
+ * provided context since the last initialisation or reset call, is
+ * computed and written in the buffer pointed to by `out`. The context
+ * itself is not modified, so extra bytes may be injected afterwards
+ * to continue that computation.
+ *
+ * \param ctx pointer to the context structure.
+ * \param out destination buffer for the hash output.
+ */
void br_md5sha1_out(const br_md5sha1_context *ctx, void *out);
+
+/**
+ * \brief Save MD5+SHA-1 running state.
+ *
+ * The running state for MD5+SHA-1 (output of the last internal block
+ * processing) is written in the buffer pointed to by `out`. The
+ * number of bytes injected since the last initialisation or reset
+ * call is returned. The context is not modified.
+ *
+ * \param ctx pointer to the context structure.
+ * \param out destination buffer for the running state.
+ * \return the injected total byte length.
+ */
uint64_t br_md5sha1_state(const br_md5sha1_context *ctx, void *out);
+
+/**
+ * \brief Restore MD5+SHA-1 running state.
+ *
+ * The running state for MD5+SHA-1 is set to the provided values.
+ *
+ * \param ctx pointer to the context structure.
+ * \param stb source buffer for the running state.
+ * \param count the injected total byte length.
+ */
void br_md5sha1_set_state(br_md5sha1_context *ctx,
const void *stb, uint64_t count);
-/*
- * The br_hash_compat_context type is a type which is large enough to
+/**
+ * \brief Aggregate context for configurable hash function support.
+ *
+ * The `br_hash_compat_context` type is a type which is large enough to
* serve as context for all standard hash functions defined above.
*/
typedef union {
br_sha256_context sha256;
br_sha384_context sha384;
br_sha512_context sha512;
+ br_md5sha1_context md5sha1;
} br_hash_compat_context;
/*
* the set implementation pointers.
*/
+/**
+ * \brief Multi-hasher context structure.
+ *
+ * The multi-hasher runs up to six hash functions in the standard TLS list
+ * (MD5, SHA-1, SHA-224, SHA-256, SHA-384 and SHA-512) in parallel, over
+ * the same input.
+ *
+ * The multi-hasher does _not_ follow the OOP structure with a vtable.
+ * Instead, it is configured with the vtables of the hash functions it
+ * should run. Structure fields are not supposed to be accessed directly.
+ */
typedef struct {
+#ifndef BR_DOXYGEN_IGNORE
unsigned char buf[128];
uint64_t count;
uint32_t val_32[25];
uint64_t val_64[16];
const br_hash_class *impl[6];
+#endif
} br_multihash_context;
-/*
- * Clear a complete multihash context. This should always be called once
- * on a given context, before setting implementation pointers.
+/**
+ * \brief Clear a multi-hasher context.
+ *
+ * This should always be called once on a given context, _before_ setting
+ * the implementation pointers.
+ *
+ * \param ctx the multi-hasher context.
*/
void br_multihash_zero(br_multihash_context *ctx);
-/*
- * Set a hash function implementation, identified by ID.
+/**
+ * \brief Set a hash function implementation.
+ *
+ * Implementations shall be set _after_ clearing the context (with
+ * `br_multihash_zero()`) but _before_ initialising the computation
+ * (with `br_multihash_init()`). The hash function implementation
+ * MUST be one of the standard hash functions (MD5, SHA-1, SHA-224,
+ * SHA-256, SHA-384 or SHA-512); it may also be `NULL` to remove
+ * an implementation from the multi-hasher.
+ *
+ * \param ctx the multi-hasher context.
+ * \param id the hash function symbolic identifier.
+ * \param impl the hash function vtable, or `NULL`.
*/
static inline void
br_multihash_setimpl(br_multihash_context *ctx,
ctx->impl[id - 1] = impl;
}
-/*
- * Get the configured hash implementation, identified by ID. This returns
- * NULL for unsupported hash implementations. The hash identifier MUST
- * be a valid one (from br_md5_ID to br_sha512_ID, inclusive).
+/**
+ * \brief Get a hash function implementation.
+ *
+ * This function returns the currently configured vtable for a given
+ * hash function (by symbolic ID). If no such function was configured in
+ * the provided multi-hasher context, then this function returns `NULL`.
+ *
+ * \param ctx the multi-hasher context.
+ * \param id the hash function symbolic identifier.
+ * \return the hash function vtable, or `NULL`.
*/
static inline const br_hash_class *
br_multihash_getimpl(const br_multihash_context *ctx, int id)
return ctx->impl[id - 1];
}
-/*
- * Reset a multihash context. The hash functions for which implementation
- * pointers have been set are reset and initialized.
+/**
+ * \brief Reset a multi-hasher context.
+ *
+ * This function prepares the context for a new hashing computation,
+ * for all implementations configured at that point.
+ *
+ * \param ctx the multi-hasher context.
*/
void br_multihash_init(br_multihash_context *ctx);
-/*
- * Input some bytes into the context.
+/**
+ * \brief Inject some data bytes in a running multi-hashing computation.
+ *
+ * The provided context is updated with some data bytes. If the number
+ * of bytes (`len`) is zero, then the data pointer (`data`) is ignored
+ * and may be `NULL`, and this function does nothing.
+ *
+ * \param ctx pointer to the context structure.
+ * \param data pointer to the injected data.
+ * \param len injected data length (in bytes).
*/
void br_multihash_update(br_multihash_context *ctx,
const void *data, size_t len);
-/*
- * Get the hash of the bytes injected so far, with the specified hash
- * function. The hash function is given by ID (e.g. br_md5_ID for MD5).
- * The hash output is written on 'dst'. The hash length is returned (in
- * bytes); if the specified hash function is not implemented by this
- * context, then this function returns 0.
+/**
+ * \brief Compute a hash output from a multi-hasher.
+ *
+ * The hash output for the concatenation of all bytes injected in the
+ * provided context since the last initialisation or reset call, is
+ * computed and written in the buffer pointed to by `dst`. The hash
+ * function to use is identified by `id` and must be one of the standard
+ * hash functions. If that hash function was indeed configured in the
+ * multi-hasher context, the corresponding hash value is written in
+ * `dst` and its length (in bytes) is returned. If the hash function
+ * was _not_ configured, then nothing is written in `dst` and 0 is
+ * returned.
+ *
+ * The context itself is not modified, so extra bytes may be injected
+ * afterwards to continue the hash computations.
*
- * Obtaining the hash output does not invalidate the current hashing
- * operation, thus "partial hashes" can be obtained.
+ * \param ctx pointer to the context structure.
+ * \param id the hash function symbolic identifier.
+ * \param dst destination buffer for the hash output.
+ * \return the hash output length (in bytes), or 0.
*/
size_t br_multihash_out(const br_multihash_context *ctx, int id, void *dst);
-/*
- * Type for a GHASH implementation. GHASH is a sort of keyed hash meant
- * to be used to implement GCM in combination with a block cipher (with
- * 16-byte blocks).
+/**
+ * \brief Type for a GHASH implementation.
+ *
+ * GHASH is a sort of keyed hash meant to be used to implement GCM in
+ * combination with a block cipher (with 16-byte blocks).
*
- * The y[] array has length 16 bytes and is used for input and output; in
- * a complete GHASH run, it starts with an all-zero value. h[] is a 16-byte
+ * The `y` array has length 16 bytes and is used for input and output; in
+ * a complete GHASH run, it starts with an all-zero value. `h` is a 16-byte
* value that serves as key (it is derived from the encryption key in GCM,
- * using the block cipher). The data length (len) is expressed in bytes.
+ * using the block cipher). The data length (`len`) is expressed in bytes.
+ * The `y` array is updated.
*
* If the data length is not a multiple of 16, then the data is implicitly
* padded with zeros up to the next multiple of 16. Thus, when using GHASH
* in GCM, this method may be called twice, for the associated data and
* for the ciphertext, respectively; the zero-padding implements exactly
* the GCM rules.
+ *
+ * \param y the array to update.
+ * \param h the GHASH key.
+ * \param data the input data (may be `NULL` if `len` is zero).
+ * \param len the input data length (in bytes).
*/
typedef void (*br_ghash)(void *y, const void *h, const void *data, size_t len);
-/*
- * Implementation of GHASH using normal 32x32->64 multiplications. It is
- * constant-time (if multiplications are constant-time).
+/**
+ * \brief GHASH implementation using multiplications (mixed 32-bit).
+ *
+ * This implementation uses multiplications of 32-bit values, with a
+ * 64-bit result. It is constant-time (if multiplications are
+ * constant-time).
+ *
+ * \param y the array to update.
+ * \param h the GHASH key.
+ * \param data the input data (may be `NULL` if `len` is zero).
+ * \param len the input data length (in bytes).
*/
void br_ghash_ctmul(void *y, const void *h, const void *data, size_t len);
-/*
- * Implementation of GHASH using normal 32x32->32 multiplications; this
- * may be faster than br_ghash_ctmul() on platforms for which the inner
- * multiplication opcode does not yield the upper 32 bits of the product.
- * It is constant-time (if multiplications are constant-time).
+/**
+ * \brief GHASH implementation using multiplications (strict 32-bit).
+ *
+ * This implementation uses multiplications of 32-bit values, with a
+ * 32-bit result. It is usually somewhat slower than `br_ghash_ctmul()`,
+ * but it is expected to be faster on architectures for which the
+ * 32-bit multiplication opcode does not yield the upper 32 bits of the
+ * product. It is constant-time (if multiplications are constant-time).
+ *
+ * \param y the array to update.
+ * \param h the GHASH key.
+ * \param data the input data (may be `NULL` if `len` is zero).
+ * \param len the input data length (in bytes).
*/
void br_ghash_ctmul32(void *y, const void *h, const void *data, size_t len);
-/*
- * Implementation of GHASH using 64x64->64 multiplications. It is
- * constant-time (if multiplications are constant-time).
+/**
+ * \brief GHASH implementation using multiplications (64-bit).
+ *
+ * This implementation uses multiplications of 64-bit values, with a
+ * 64-bit result. It is constant-time (if multiplications are
+ * constant-time). It is substantially faster than `br_ghash_ctmul()`
+ * and `br_ghash_ctmul32()` on most 64-bit architectures.
+ *
+ * \param y the array to update.
+ * \param h the GHASH key.
+ * \param data the input data (may be `NULL` if `len` is zero).
+ * \param len the input data length (in bytes).
*/
void br_ghash_ctmul64(void *y, const void *h, const void *data, size_t len);
+/**
+ * \brief GHASH implementation using the `pclmulqdq` opcode (part of the
+ * AES-NI instructions).
+ *
+ * This implementation is available only on x86 platforms where the
+ * compiler supports the relevant intrinsic functions. Even if the
+ * compiler supports these functions, the local CPU might not support
+ * the `pclmulqdq` opcode, meaning that a call will fail with an
+ * illegal instruction exception. To safely obtain a pointer to this
+ * function when supported (or 0 otherwise), use `br_ghash_pclmul_get()`.
+ *
+ * \param y the array to update.
+ * \param h the GHASH key.
+ * \param data the input data (may be `NULL` if `len` is zero).
+ * \param len the input data length (in bytes).
+ */
+void br_ghash_pclmul(void *y, const void *h, const void *data, size_t len);
+
+/**
+ * \brief Obtain the `pclmul` GHASH implementation, if available.
+ *
+ * If the `pclmul` implementation was compiled in the library (depending
+ * on the compiler abilities) _and_ the local CPU appears to support the
+ * opcode, then this function will return a pointer to the
+ * `br_ghash_pclmul()` function. Otherwise, it will return `0`.
+ *
+ * \return the `pclmul` GHASH implementation, or `0`.
+ */
+br_ghash br_ghash_pclmul_get(void);
+
+/**
+ * \brief GHASH implementation using the POWER8 opcodes.
+ *
+ * This implementation is available only on POWER8 platforms (and later).
+ * To safely obtain a pointer to this function when supported (or 0
+ * otherwise), use `br_ghash_pwr8_get()`.
+ *
+ * \param y the array to update.
+ * \param h the GHASH key.
+ * \param data the input data (may be `NULL` if `len` is zero).
+ * \param len the input data length (in bytes).
+ */
+void br_ghash_pwr8(void *y, const void *h, const void *data, size_t len);
+
+/**
+ * \brief Obtain the `pwr8` GHASH implementation, if available.
+ *
+ * If the `pwr8` implementation was compiled in the library (depending
+ * on the compiler abilities) _and_ the local CPU appears to support the
+ * opcode, then this function will return a pointer to the
+ * `br_ghash_pwr8()` function. Otherwise, it will return `0`.
+ *
+ * \return the `pwr8` GHASH implementation, or `0`.
+ */
+br_ghash br_ghash_pwr8_get(void);
+
#endif
projects / BearSSL / blobdiff